This invention relates to dispensing and dispensing systems for applying materials to substrates. In particular, this invention relates to the dispensing of adhesives, sealants, caulks, fluxes, encapsulants, and paints. This invention is especially suited to those dispensing applications which require assurance that the material has been deposited onto the substrate and which includes a means for having redundant dispensing so that production may continue in the event of a failure.
Applying a liquid material, in particular, an adhesive, by means of an applicator to a substrate in a controlled manner is well known. Applicators, otherwise known as dispensers, guns, or valves, particularly to apply materials to a substrate for adhesion (adhesives, fluxes, etc.) and sealing (paints, encapsulants, etc.). It is also known to provide detection systems (ultraviolet, infrared, vision, etc.) to determine if the material has properly been dispensed. If the material has not been properly dispensed, the substrate may be rejected and/or the line shut down. However, in many applications, failure to properly apply the material to the substrate may cause damage to the substrate and/or cause the substrate or its contents to interfere with the line thereby causing unnecessary down time. For example, in the packaging of beverages, the failure to properly seal the case or carton, may result in the cans spilling from the container onto the conveyor and/or the production floor. The cans may rupture, thereby spilling their contents or may jam the conveying system or otherwise interfere with the transportation of other properly sealed containers. This results in unnecessary down time in cleaning up this accident.
Accordingly, there is a need to provide dispensing systems which not only accurately apply material to a substrate, but in the event of a failure, provide a means for maintaining production, until the failure of the dispenser may be rectified at the scheduled down time of the line thereby maintaining production.
An object of the present invention is to provide a method and apparatus for dispensing material onto a substrate wherein upon the failure of a dispenser, another dispenser will automatically perform the function of the failed dispenser. This has the advantage of maintaining production until the failed dispenser may be serviced at a more convenient time, such as at the end of a normal production shift. This may be accomplished, by utilizing a standby or secondary dispenser should the first gun fail.
These and other objects, features, and advantages can be accomplished by causing a dispenser to dispense a first pattern of material onto a substrate; causing another dispenser to dispense a second pattern of material onto the substrate; and upon the detection of the failure of material to be dispensed by one of the dispensers, automatically causing the other dispenser to dispense both first and second patterns of material onto the substrate.
These and other objects, features, and advantages can also be accomplished by a method for depositing a material pattern onto a substrate comprising the steps of: dispensing material from a first dispenser so as to deposit a first portion of the pattern of material on the substrate; then dispensing material from a second dispenser to deposit a second portion of the pattern of material on the substrate; sensing the material dispensed from said first and second sensors; and upon determining the absence of the first or second portion of the pattern of material dispensed, automatically causing one of said dispensers to deposit both the first and second portions of the pattern of material to be deposited onto a subsequent substrate.
These and other objects, features, and advantages can be further accomplished by a method for dispensing material comprising the steps of: determining a first actuation sequence; determining a second actuation sequence; determining a third actuation sequence; controlling the actuation of a first dispenser, for dispensing material, in accordance with the first actuation sequence; controlling the actuation of a second dispenser for dispensing material, in accordance with the second actuation sequence; detecting the failure of the first dispenser to dispense the material; and controlling the actuation of the second dispenser in accordance with the third actuation sequence.
These and other objects, features, and advantages can be further accomplished by a method for dispensing adhesive onto a substrate in a pattern having a plurality of discrete adhesive deposits comprising the steps of: a) alternating the actuation of two adhesive dispensers, to dispense discrete streams or drops of adhesive onto the substrate in a pattern; b) sensing the dispensed adhesive; and c) upon the detection of a failure to dispense adhesive, causing a de-activation of the dispenser failing to dispense the adhesive and causing the other dispenser to be actuated to dispense the discrete streams or drops of adhesive from the discharge orifice in order to maintain said pattern.
These and other objects, features, and advantages can be further accomplished by a method of dispensing adhesive onto a substrate comprising the steps of: a) dispensing the adhesive from a first dispenser onto a substrate to produce a first dispensed pattern while maintaining a second dispenser in a standby condition; b) cycling the dispensers from standby to dispense and from dispense to standby after one of the following: i) a period of time, ii) a number of gun firings, or iii) a number of substrates; and c) upon receiving a signal indicating the failure to detect the proper amount of adhesive dispensed, automatically de-activating the dispenser while causing the dispenser in standby to be actuated to dispense the adhesive onto the substrate to produce the first dispensed pattern on at least a subsequent substrate.